A paper or non-woven web can be used for various purposes. Examples thereof include the use as packaging material, such as for food packaging; filter material, such as for infusion beverages, e.g. tea and coffee, or for oil filtration; composite laminates, such as overlay paper; metallized paper suitable for labels or packages; air laid non-woven webs, such as hygiene and personal care products, home care products, e.g. wipes, towels, napkins and tablecloths, speciality papers, e.g. wallcoverings (wall paper), mattress and upholstery padding, just to name a few.
Depending on its use, a paper or non-woven web has to fulfil various properties, such as tensile strength in a dry state and/or in a wet state, porosity, adherence, wettability, hydrophilicity/hydrophobicity. After use, it might be necessary or advantageous that the paper or non-woven web can be decomposed. Accordingly, biodegradability is a further often desired property of a paper or non-woven web.
A paper or non-woven web typically comprises fibers mainly constituting the web, which may be natural fibers or synthetic fibers. In order to impart the desired properties to a paper or non-woven web, it is often necessary to modify its composition.
EP 0 943 731 A1 describes a filter material which controls wettability and water absorption by using an additive of an amphiphilic compound, such as carboxymethyl cellulose (CMC), or hydrophilic and hydrophobic compounds, such as styrene/acrylate copolymers.
However, the present inventors have found that the polysaccharides alone, proposed in EP 0 943 731 A1 as amphiphilic or hydrophilic compounds, provide fiber-fiber crosslinkages which are stable in a dry state, however insufficient in a wet state. While the hydrophobic compounds, such as styrene/acrylate copolymers, proposed in EP 0 943 731 A1 provide better wet-strength properties, they are based on mineral oil and therefore not desired from a viewpoint of conservation of resources and biodegradability.